I asked this on the LoL bug reports board, but I found no answer.
To make a long story short, these are the things that happened to my computer:
My Patcher updated to the Spectator Patch, as I started watching some featured matches my computer crashed (BSoD). Apparently, my computer used an earlier system restore point and whenever I tried to play LoL again, the patcher would work but the client never run correctly after clicking "Play".
I updated my graphics card drivers and reinstalled the game, but the client just doesn't run. I was worried I wouldn't be able to play games on this laptop anymore but there is no problem when I run TF2 or other Steam games.
Help anyone? I also tried the repair button on the patcher, the client still refuses to show up.